1. Field of Invention
This invention relates to bowling ball return systems for bowling alleys, and particularly to an improved ball lift assembly for such a system and the ball lift belt thereof.
2. Description of Prior Art
This ball lift assembly is for use as a replacement for the original equipment ball lift assembly in AMF's (American Machine and Foundry's) ball return systems identified by AMF as their earlier KICKER ROLLER SYSTEM and their current P.B.L. (Positive Ball Lift System). Both these systems are currently in use.
In the Kicker Roller System, applicant's improved assembly replaces the ball return belt, and also the following items are eliminated: the ball door exit and the kicker roller assembly. In this system, kicker wheels spin around rubbing against the ball to force the ball up the track to the wedge position between a belt and the track. Once wedged, the belt's friction and movement carries the ball to the top of the lift. However, oil on the bowling lane is picked up by the ball as it rolls down the lane. Some of this oil gets deposited on the kicker wheels, creating slipping between the ball and the wheels, and the ball never reaches the wedge position resulting in a stuck ball. When this system was first introduced by AMF, it worked satisfactorily because there was much less oil used on the bowling lane. In recent years, with the much improved bowling balls, bowling lanes place much more oil on the lanes to control the ball's curving. This additional oil has created the problem that exists today, for this additional oil causes the additional deposits on the kicker wheels.
The newer system (P.B.L.) does not use kickers. This system allows the ball to free-fall into the ball exit opening and under the ball lift belt, onto a pressure plate referred to as the lift arm assembly. The ball pressure on the track rail assembly activates a ratchet assembly which raises the plate that the ball landed on. This raising pushes the ball up between the ball lift belt and the lift rail, creating the wedge of the ball between these items needed to lift the ball up the lift rail. The P.B.L. system pushes the ball up only a matter of inches, creating a weak partial wedge. Oil on the ball allows slippage and the ball falls back down, causing reactivation of the pressure plate to go up and come down again repeatedly, creating a yo-yo effect and a stuck ball.